This invention relates to the art of forming toner images on a charge retentive surface and, in particular to an apparatus for removing residual toner material from the photoconductive surface of an automatic xerographic reproducing apparatus.
In the art of xerography, a charge retentive surface generally comprising a photoconductive insulating material adhered to a conductive backing is charged uniformly. Then, the uniformly charged plate is exposed to a light image of an original document to be reproduced. The latent electrostatic images, thus formed, are rendered visible by applying any one of numerous pigmented resins specifically designed for this purpose. In the case of a reusable photoconductor, the pigmented resin, more commonly referred to as toner, which forms the visible images is transferred to plain paper.
Although a preponderance of the toner forming the images is transferred to the paper during transfer, some toner remains on the photoconductor surface, it being held thereto by relatively high electrostatic and/or mechanical forces. It is essential for optimum operation that the toner remaining on the surface be cleaned therefrom.
A commercially successful mode of cleaning employed in automatic xerography utilizes a brush with soft bristles which have suitable triboelectric characteristics. While the bristles are soft they are sufficiently firm to remove residual toner particles from the xerographic plate. In addition, webs or belts of soft fibrous or tacky materials and other cleaning systems are known.
In spite of the successes that have been achieved in removing residual toner from photoconductor surfaces there is still room for improvement. This is especially true in the case where single component magnetic toners are employed for forming the images. Conventional cleaning systems have not proven to be satisfactory in removing such toners from the charge retentive surface.
Toner image disturbance prior to removal from the charge retentive surface has been practiced as an adjust to the removal of residual toner from charge retentive surfaces. An example of such an arrangement is illustrated in U.S. Pat. No. 3,617,123 utilizes a vibrating brush as an adjunct to the cleaning effect by the developer system. There the vibrating brush is positioned upstream from the point where the photoconductor drum surface enters a combination development and cleaning. The brush is mounted longitudinally along the drum surface so that the brush fibers are in light touching contact with the surface to be cleaned and is vibrated transversely across the drum surface. Thus, the brush serves to reposition or puddle the charged residual toner particles over the drum so that they can be more readily removed by the combination development and cleaning system. A brush of this type physically dislodges the built-up residual toner and tends to spread it over the imaging surface. However, after periods of extended use the toner becomes impregnated in the bristles of the brush resulting in the brush becoming ineffective for its intended purpose.
Conductive brushes which are moved transversely to the direction of movement of the charge retentive surface are also known as illustrated in U.S. patent application Ser. No. 438,227 filed in the name of Lloyd F. Bean et al which is assigned to the same assignee as the instant application.
It is well known that the types of fiber brushes disclosed in U.S. Pat. No. 3,617,123 and the aforementioned application shed fibers which cause problems in the image making process. It will be appreciated that a residual toner removal apparatus that utilizes members (i.e. disturber and cleaning brush) that do not contain such fibers is desirable. Accordingly, as will be discussed hereinbelow, I have provided such a structure.